Planar antennas are finding increasing popularity owing to their low profile, light weight, and possible conformity to supporting structures. The most serious limitation of these antennas is the narrow bandwidth of the single element. The traditional microstrip patch antenna has an impedance bandwidth of only few percent. Several methods have been used to widen the impedance bandwidth of the patch antenna. See, e.g., D. M. Pozar and D. H. Schaubert, editors, "A review of bandwidth enhancement techniques for microstrip antennas", Microstrip Antennas, the Analysis and Design of Microstrip Antennas and Arrays, IEEE press, pp. 157-166, 1995, which is hereby incorporated by reference in its entirety. Parasitic elements can be stacked together with the driven element in a multilayer configuration. See, e.g., F. Croq and D. M. Pozar, "Millimeter wave design of wide-band slot coupled stacked microstrip antennas", IEEE Trans. Antennas Propagation, vol. 39, pp. 1770-1776, Dec. 1991, which is hereby incorporated by reference in its entirety. The difference in size of the two resonators results in a bandwidth of 10-20%. Several log-periodically scaled microstrip patches can be series-fed to achieve an impedance bandwidth of 22%. See, e.g., H. Pues, J. Bogaers, R. Pieck and A. Van de Capelle, "Wideband quasi-log-periodic microstrip antenna", IEE Proc. Vol. 128, Part H., pp. 159-163, June 1981, which is hereby incorporated by reference in its entirety.